Electric snap switch



July 31, 1934. P. cs. SHAW ELECTRIC SNAP SWITCH Filed Jan. 18, 1933 2 Sheets-Sheet l w swam wl m g July 31, 1934.

P. G. SHAW ELECTRIC SNAP SWITCH Filed Jan. 18, 1933 2 Sheets-Sheet 2 Ill Invent OY: Pew c q G. S h aw, 1 M

Patented July 31, 1934 ELECTRIC SNAP SWITCH Percy G. Shaw, Bridgeport, Com, assignor to General Electric Company, a

,New York corporation of Application January 18, 1933, Serial No. 652,311

1 Claim. (Cl. 20067) The present invention relates to electric snap switches and especially to electric snap switches adapted to carry currents of a. relatively high value for such type of switch, for example, currents of the order of 30 amperes. The carrying of a current of this order requires the use of relatively heavy contact parts. Also, it requires a substantial movement apart of the contacts with a quick snap action in order to prevent destructive arcing.

Heretofore to meet these requirements, snap switches have been relatively large, a thing which is disadvantageous, especially for certain uses.

One object of the present invention is to provide an improved switch of this type which, while capable of carrying a current of relatively high value, is unusually small and compact; which, in fact, may be built of a size to fit a standard wall or outlet box such as is used in house wiring.

, A further object of the invention is to provide an improvement switch mechanism which may be mounted either on the underside of a cover plate for mounting flush in an outlet box or on a base for surface mounting.

Other objects and the advantages of my invention are pointed out more fully in the following specification.

In the drawings, Fig. 1 is a sectional view of a switch embodying my invention; Fig. 2 is a sectional view taken at right angles to Fig. 1; Fig. 3 is an exploded view showing in perspective the parts which go to make up the switch; Fig. 4 is a side view partly in section of another embodiment of the invention; Fig. 5 is an end view of the structure shown in Fig. 4; and Fig. 6 is a top plan view thereof.

Referring to the drawings, Figs. 1 to 3 inclusive, 1 indicates a cover which carries the fixed contacts and the switch movement, and 2 indicates a box which encloses them. Both the cover and the box are'formed from suitable insulating material.

On the upper side of the cover at each corner is a recess 3 adapted to house the head of binding screw 4 which threads into a metal sleeve 5 fastened in the bottom wall of each recess. In the bottom wall of each recess directly adjacent to sleeve 5 is a slot 6. The sleeve 5 in conjunction with the adjacent slot 6 serves to hold in place the fixed switch contacts '7. A fixed switch .contact '7 may be located at each corner of the cover or at only certain of the comers according to the type of switch, that is to say according to whether a single or double pole switch 'is desired, or a three way switch. In the present instance, two contacts '7v located on one side of the switch are illustrated, thereby providing a single pole, double break switch. Fixed contacts '7 extend through slots 6 and are provided wings 8 which lie against the. bottom walls of recesses 3 and are fastened in place by sleeves 5, the upper ends of the sleeves being peened over the wings, as is indicated at 9. By this arrangement, each sleeve 5 performs a double function in that it serves as an insert for the binding screw and in conjunction with the adjacent slot 6 serves as a fastening means for the fixed con tact. The sleeve 5 holds the contact in place while the slot 6 serves to keep it from turning. Thus, the contact is firmly held in position so that additional screws for holding the contact in place are not required. This is one important feature of my invention in that within the limits of a relatively small space it permits of the use of a sleeve and binding screw of'a size capable of carrying a current ofrelatively high value for this type of switch and fastening in place a conductor of a size required for such a current.

The cover plate is provided with ears 10 for use in mounting it in a standard outlet box, a slot .11 for the switch handle, and openings 12 for the reception of screws 13 which fasten the switch movement to the underside of the cover.

The switch movement comprises a U-shaped frame 14 having ears 15 which rest against the underside of cover 1 and are provided with tapped openings which receive the screws 13. The side walls of frame 14 are cut away to provide transversely extending arcuate slots 16 in which the upper end of a U-shaped yoke 1'7 moves. It is provided also with notchedparts which provide pivot sockets 18 on which shoulders 19 of yoke 17 pivot. Pivoted at the upper ends of the side walls of frame 14 is an actuating means or trigger 20 which is supported on a pin 21 which extends through openings in the frame and trigger. The lower end of the trigger is in the form of an arm which projects inward terminating between the lower ends of the arms of yoke 17. Connected to yoke 1'7 and to the lower end of the trigger arm is an actuating spring 22, the upper end of which engages in a notch in the cross piece of yoke 17, the lower end of which engages in a notch in the lower end of trigger 20. Fastened to trigger 20 is a switch button or switch handle 23, the upper end of which projects through slot 11 in cover 1. By moving handle 23, trigger 20 is turned on pivot pin 21 and effects a snap action movement of yoke 17 back and forth on pivots 18, due to spring 22 being moved from one side to the other of its center line. This is a known type of switch movement, the operation of which is well understood. The movement back and forth of yoke 17 is limited by stops 24 on the side walls of frame 14, such stops being shown in the present instance as being formed by projections struck out from the material of the side walls. The movement of trigger 20 is limited by' at their upper edges with angularly extending means of stops 25 which project upward from the bottom wall of frame 14. The actuating means or trigger 20 is provided with yoke engaging parts or projections 26 which engage yoke 17, in case it does not move readily under the action of spring 22, to give it an initial movement. In other words, these parts serve as a positive starting means for the switch movement.

Carried by yoke 17 is a movable contact 27 comprising two parallel contacting plates having projecting ears 28 and 29 which engage fixed contacts '7 on opposite sides, contacts 7 being wedged between the two parts of each ear. Ears 28 and 29 are provided with angularly extending projecting wings 30 which serve to guide cars 28 and 29 on to contacts 7. Movable contact 27 is fixed rigidly to one arm of yoke 17 by means of rivets 31 integral with such arm. On opposite sides of contact 27 are arranged plates 32 of insulating material which serve as are snufl'ers, the projections 33 on the plates lying between and in line with ears 28 and 29. Contact 27 and plates 32 are held between suitable metal washers 34.

In the present instance, a contact 27 is carried on only one side of yoke 17. However, in case of a double pole switch or a three-way switch, a contact may be carried by each arm of yoke 17. In this case, the contact carried by the other arm may be a duplicate of that shown.

The switch movement is enclosed in housing 2 as is shown clearly in Figs. 1 and 2, the housing being fastened in place by suitable screws which extend through openings 35 in its bottom wall and thread into the bottom wall of frame 14.

In operation, the switch may be moved from one position to the other by means of button 23. As the button is turned,'the tension on spring 22 is increased. At the same time, trigger 20 moves the lower end of the spring across dead center. After the spring moves across dead center, yoke 17 is caused to move from engagement with one set of stops 24 intoengagement with the other set of stops 24 with a quick snap action. At the same time, the movement of trigger 20 is limited by the stop 25; In case the yoke does not start to move after the switch button has been moved a certain distance, it will be engaged by one of the projections 26 and given a positive start. when the contacts 28 and 29 move from engagement with fixed contacts '1, the insulating plates 33 are carried to positions where projections 33 stand between the contacts. Thus they serve to.

assist in extinguishing the structive arcing.

By the above described arrangement, I provide a construction which is small and compact but which at the same time may be constructed of parts sufllciently heavy to enable it to carry a current of relatively high value. For example, in the case of a 30 ampere switch, a standard requirement is that the binding screw head be in diameter and that it be capable of holding in place No. 8 wire. With the above construction, substantially the entire recess 3 may be utilized for the head of the binding screw since additional space is not required for screws for fastening in position the fixed contacts. This enables me' to provide a binding screw of "the required size and at the same time to make a substantial saving in the size of the switch. In fact, it is due primarily to this arrangement that the switch may be made sufliciently small to flt in a standard outlet box.

In Figs. 4, 5 and 6 is shown a modification of the invention adapted for surface mounting. In

arc, preventing dethe case of a switch for surface mounting, the requirements as to size are not so rigid as in the case of a switch to be mounted in an outlet box. In this case, therefore, I do not utilize sleeves 5, as shown in Figs. 1, 2 and 3 for fastening the fixed contacts in place, but fasten them in place by additional screws. Referring to Figs. 4, 5 and 6, 40 indicates a base of suitable insulating material provided with longitudinally extending recesses 41 and 42 on opposite sides. Mounted at the four corners of base 40 are fixed contacts43 which project down into recesses 41 and 42. Each contact is provided with an angularly extending wing 44 which engages the upper surface of the base at its comer and is fastened to the base by screws 45. In each wing 44 is an opening into which is threaded a binding Post 46. Binding post 46 assists in holding the fixed contact in position.

The switch movement shown in Figs. 4, 5 and 6 is the same in structure as that shown in Figs. 1 to 3 inclusive, except that the movable contacts instead of projecting upwardly parallel to the frame, as shown particularly in Fig. 1, depends downward as best shown in Fig. 4. In other words, the movable contacts are turned through an angle of 180 degrees relatively to the yoke from the position shown in Fig. 1. The switch movement in Figs. 4, 5 and 6 is indicated generally by the reference numeral 47, the switch handle being indicated at 48 and the movable contact at 49. In the construction shown in Figs. 4, 5 and 6, a movable contact is shown attached to each arm of the yoke, thereby providing a double pole, double break switch. The operation of the switch movement shown in Figs. 4, 5 and 6 is the same as that shown in Figs. 1, 2 and 3, and hence does not require further description.

Base 40 is provided with openings 50 for the reception of suitable screws for fastening the base to a support and with openings 51 for the lead wires.

Considering the arrangement shown in Figs. 1 to 3 inclusive in connection with that shown in Figs. 4 to 6, it will be seen that by my improved switch construction, I am enabled to provide a movable contact on either one or both sides of the yoke and am enabled to arrange the movable contacts so that they project either upwardly or downwardly relatively to the yoke. This enables the same switch movement to be adapted to a number of different combinations.

whatlclaimasnewanddesiretosecure by Letters Patent 01' the United States is:

In a switch structure, the combination of a cover plate of insulating material having recesses at a plurality of its corners, a contact slot in the bottom wall of each recess, and a central slot, a switch contact for each recess having a wing which rests on the bottom of its recess and a contact portion which projects downwardly through the contact slot to the underside of the cover plate, a binding screw in each wing, a switch movement connected to the underside of said cover plate for cooperation with said contacts and provided with a switch handle projecting upwardly through said central slot, supporting cars at opposite ends of the cover for mounting the structure in an outlet box, and a casing of insulating material enclosing the switch movement and to which the cover is connected.

mar a. srmw. 

